A common method of harnessing this thermal energy is to use it to boil water to produce pressurized steam which will then drive a steam turbine that turns an alternator and generates electricity. ==Early reactors== The neutron was discovered in 1932 by British physicist James Chadwick.
The concept of a nuclear chain reaction brought about by nuclear reactions mediated by neutrons was first realized shortly thereafter, by Hungarian scientist Leó Szilárd, in 1933.
Szilárd's ideas for nuclear reactors using neutron-mediated nuclear chain reactions in light elements proved unworkable. Inspiration for a new type of reactor using uranium came from the discovery by Lise Meitner, Fritz Strassmann and Otto Hahn in 1938 that bombardment of uranium with neutrons (provided by an alpha-on-beryllium fusion reaction, a "neutron howitzer") produced a barium residue, which they reasoned was created by the fissioning of the uranium nuclei.
Subsequent studies in early 1939 (one of them by Szilárd and Fermi) revealed that several neutrons were also released during the fissioning, making available the opportunity for the nuclear chain reaction that Szilárd had envisioned six years previously. On 2 August 1939 Albert Einstein signed a letter to President Franklin D.
government. Shortly after, Hitler's Germany invaded Poland in 1939, starting World War II in Europe.
While an ongoing rich research topic since at least the 1940s, no self-sustaining fusion reactor for power generation has ever been built. ====By moderator material==== Used by thermal reactors: Graphite-moderated reactors Water moderated reactors *Heavy-water reactors (Used in Canada, India, Argentina, China, Pakistan, Romania and South Korea). * Light-water-moderated reactors (LWRs).
The memorandum was a product of the MAUD Committee, which was working on the UK atomic bomb project, known as Tube Alloys, later to be subsumed within the Manhattan Project. Eventually, the first artificial nuclear reactor, Chicago Pile-1, was constructed at the University of Chicago, by a team led by Italian physicist Enrico Fermi, in late 1942.
The Chicago Pile achieved criticality on 2 December 1942 at 3:25 PM.
military developed a number of nuclear reactors for the Manhattan Project starting in 1943.
Fermi and Szilard applied for a patent on reactors on 19 December 1944.
Despite research having started in the 1950s, no commercial fusion reactor is expected before 2050.
Atomic Energy Commission produced 0.8 kW in a test on 20 December 1951 and 100 kW (electrical) the following day, having a design output of 200 kW (electrical). Besides the military uses of nuclear reactors, there were political reasons to pursue civilian use of atomic energy.
President Dwight Eisenhower made his famous Atoms for Peace speech to the UN General Assembly on 8 December 1953.
institutions and worldwide. The first nuclear power plant built for civil purposes was the AM-1 Obninsk Nuclear Power Plant, launched on 27 June 1954 in the Soviet Union.
The EBR-I, the first reactor to have a core meltdown, in 1955, was also a sodium-cooled reactor. Pebble-bed reactors (PBR) [moderator: graphite; coolant: helium] : These use fuel molded into ceramic balls, and then circulate gas through the balls.
The concept of a natural nuclear reactor was theorized as early as 1956 by Paul Kuroda at the University of Arkansas. Such reactors can no longer form on Earth in its present geologic period.
First discovered in 1972 by French physicist Francis Perrin, they are collectively known as the Oklo Fossil Reactors.
This reactor design could also function as a rocket engine, as featured in Harry Harrison's 1976 science-fiction novel Skyfall.
The former include the advanced boiling water reactor (ABWR), two of which are now operating with others under construction, and the planned passively safe Economic Simplified Boiling Water Reactor (ESBWR) and AP1000 units (see Nuclear Power 2010 Program). The Integral fast reactor (IFR) was built, tested and evaluated during the 1980s and then retired under the Clinton administration in the 1990s due to nuclear non-proliferation policies of the administration.
The former include the advanced boiling water reactor (ABWR), two of which are now operating with others under construction, and the planned passively safe Economic Simplified Boiling Water Reactor (ESBWR) and AP1000 units (see Nuclear Power 2010 Program). The Integral fast reactor (IFR) was built, tested and evaluated during the 1980s and then retired under the Clinton administration in the 1990s due to nuclear non-proliferation policies of the administration.
The Monju reactor in Japan suffered a sodium leak in 1995 and could not be restarted until May 2010.
An interdisciplinary team from MIT has estimated that given the expected growth of nuclear power from 2005 to 2055, at least four serious nuclear accidents would be expected in that period. ==Nuclear accidents== Serious, though rare, nuclear and radiation accidents have occurred.
As of April 2006, only five AHRs were in operation. ===Future and developing technologies=== ====Advanced reactors==== More than a dozen advanced reactor designs are in various stages of development.
The Monju reactor in Japan suffered a sodium leak in 1995 and could not be restarted until May 2010.
The former include the advanced boiling water reactor (ABWR), two of which are now operating with others under construction, and the planned passively safe Economic Simplified Boiling Water Reactor (ESBWR) and AP1000 units (see Nuclear Power 2010 Program). The Integral fast reactor (IFR) was built, tested and evaluated during the 1980s and then retired under the Clinton administration in the 1990s due to nuclear non-proliferation policies of the administration.
These constitute the great majority of operational nuclear reactors: as of 2014, 93% of the world's nuclear reactors are water cooled, providing about 95% of the world's total nuclear generation capacity. * Pressurized water reactor (PWR) Pressurized water reactors constitute the large majority of all Western nuclear power plants. ** A primary characteristic of PWRs is a pressurizer, a specialized pressure vessel.
As of 2021, 9 remain open, mostly due to safety improvements and help from international safety agencies such as the DOE.
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